“But you will receive power when the Holy Spirit has come upon you, and you will be my witnesses in Jerusalem, and in all Judea and Samaria, and to the farthest parts of the earth.”
The book of Acts follows this program of witnessing to the world. The verse is key to the book. The Holy Spirit empowered the church to proclaim the gospel. They spoke about Jesus.
We continue the work of proclaiming Christ to the world. This is Jesus’ mission for the church in every age. It is an essential identifying mark of the church.